There is considerable interest in developing sensors that act as analogs of the mammalian olfactory system (Lundstrom et al. (1991) Nature 352:47–50; Shurmer and Gardner (1992) Sens. Act. B 8:1–11; Shurmer and Gardner (1993) Sens. Actuators B 15:32). Prior attempts to produce a broadly responsive sensor array have exploited heated metal oxide thin film resistors (Gardner et al. (1991) Sens. Act. B4:117–121; Gardner et al. (1991) Sens. Act. B 6:71–75), polymer sorption layers on the surfaces of acoustic wave resonators (Grate and Abraham (1991) Sens. Act. B 3:85–111; Grate et al. (1993) Anal. Chem. 65:1868–1881), arrays of electrochemical detectors (Stetter et al. (1986) Anal. Chem. 58:860–866; Stetter et al. (1990) Sens. Act. B 1:43–47; Stetter et al. (1993) Anal. Chem. Acta 284:1–11), conductive polymers or composites that consist of regions of conductors and regions of insulating organic materials (Pearce et al. (1993) Analyst 118:371–377; Shurmer et al. (1991) Sens. Act. B 4:29–33; Doleman et al. (1998) Anal. Chem. 70:2560–2654; Lonergan et al. Chem. Mater. 1996, 8:2298). Arrays of metal oxide thin film resistors, typically based on tin oxide (SnO2) films that have been coated with various catalysts, yield distinct, diagnostic responses for several vapors (Corcoran et al. (1993) Sens. Act. B 15:32–37). However, due to the lack of understanding of catalyst function, SnO2 arrays do not allow deliberate chemical control of the response of elements in the arrays nor reproducibility of response from array to array. Surface acoustic wave resonators are extremely sensitive to both mass and acoustic impedance changes of the coatings in array elements, but the signal transduction mechanism involves somewhat complicated electronics, requiring frequency measurement to 1 Hz while sustaining a 100 MHZ Rayleigh wave in the crystal.
Although these sensors have particular advantages there exists a need for polymer based sensor system that shows intra-array variation without necessarily changing the polymer itself. Such a system would allow simultaneous determination of kinetic and equilibrium properties of an analyte. The present invention fulfills these and other needs.